ipvs: make ip_vs_svc_table and ip_vs_svc_fwm_table per netns

Current ipvs uses one global mutex "__ip_vs_mutex" to keep the global
"ip_vs_svc_table" and "ip_vs_svc_fwm_table" safe. But when there are
tens of thousands of services from different netns in the table, it
takes a long time to look up the table, for example, using "ipvsadm
-ln" from different netns simultaneously.

We make "ip_vs_svc_table" and "ip_vs_svc_fwm_table" per netns, and we
add "service_mutex" per netns to keep these two tables safe instead of
the global "__ip_vs_mutex" in current version. To this end, looking up
services from different netns simultaneously will not get stuck,
shortening the time consumption in large-scale deployment. It can be
reproduced using the simple scripts below.

init.sh: #!/bin/bash
for((i=1;i<=4;i++));do
        ip netns add ns$i
        ip netns exec ns$i ip link set dev lo up
        ip netns exec ns$i sh add-services.sh
done

add-services.sh: #!/bin/bash
for((i=0;i<30000;i++)); do
        ipvsadm -A  -t 10.10.10.10:$((80+$i)) -s rr
done

runtest.sh: #!/bin/bash
for((i=1;i<4;i++));do
        ip netns exec ns$i ipvsadm -ln > /dev/null &
done
ip netns exec ns4 ipvsadm -ln > /dev/null

Run "sh init.sh" to initiate the network environment. Then run "time
./runtest.sh" to evaluate the time consumption. Our testbed is a 4-core
Intel Xeon ECS. The result of the original version is around 8 seconds,
while the result of the modified version is only 0.8 seconds.

Signed-off-by: Jiejian Wu <jiejian@linux.alibaba.com>
Co-developed-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20260224205048.4718-2-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 29a36709e7f3..074a204ec6db 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -33,6 +33,12 @@
 
 #define IP_VS_HDR_INVERSE	1
 #define IP_VS_HDR_ICMP		2
+/*
+ *	Hash table: for virtual service lookups
+ */
+#define IP_VS_SVC_TAB_BITS 8
+#define IP_VS_SVC_TAB_SIZE BIT(IP_VS_SVC_TAB_BITS)
+#define IP_VS_SVC_TAB_MASK (IP_VS_SVC_TAB_SIZE - 1)
 
 /* Generic access of ipvs struct */
 static inline struct netns_ipvs *net_ipvs(struct net* net)
@@ -1041,6 +1047,13 @@ struct netns_ipvs {
 	 */
 	unsigned int		mixed_address_family_dests;
 	unsigned int		hooks_afmask;	/* &1=AF_INET, &2=AF_INET6 */
+
+	/* the service mutex that protect svc_table and svc_fwm_table */
+	struct mutex service_mutex;
+	/* the service table hashed by <protocol, addr, port> */
+	struct hlist_head svc_table[IP_VS_SVC_TAB_SIZE];
+	/* the service table hashed by fwmark */
+	struct hlist_head svc_fwm_table[IP_VS_SVC_TAB_SIZE];
 };
 
 #define DEFAULT_SYNC_THRESHOLD	3